From edccc35e8fa2c546e0ef1c8efde56e6b12e3c175 Mon Sep 17 00:00:00 2001
From: Alina Sbirlea <asbirlea@google.com>
Date: Wed, 15 Apr 2020 15:58:57 -0700
Subject: [PATCH] [Reassociate] Preserve AAManager and BasicAA analyses.

Now Reassociate Pass invalidates the analysis results of AAManager and BasicAA,
but it saves GlobalsAA, although it seems that it should preserve them, since
it affects only Unary and Binary operators.

Author: kpolushin (Kirill)

Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D77137
---
 llvm/lib/Transforms/Scalar/Reassociate.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/llvm/lib/Transforms/Scalar/Reassociate.cpp b/llvm/lib/Transforms/Scalar/Reassociate.cpp
index 8b4e36a..e95526c 100644
--- a/llvm/lib/Transforms/Scalar/Reassociate.cpp
+++ b/llvm/lib/Transforms/Scalar/Reassociate.cpp
@@ -29,6 +29,7 @@
 #include "llvm/ADT/SmallSet.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/BasicAliasAnalysis.h"
 #include "llvm/Analysis/GlobalsModRef.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/Argument.h"
@@ -2457,6 +2458,8 @@ PreservedAnalyses ReassociatePass::run(Function &F, FunctionAnalysisManager &) {
   if (MadeChange) {
     PreservedAnalyses PA;
     PA.preserveSet<CFGAnalyses>();
+    PA.preserve<AAManager>();
+    PA.preserve<BasicAA>();
     PA.preserve<GlobalsAA>();
     return PA;
   }
@@ -2487,6 +2490,8 @@ namespace {
 
     void getAnalysisUsage(AnalysisUsage &AU) const override {
       AU.setPreservesCFG();
+      AU.addPreserved<AAResultsWrapperPass>();
+      AU.addPreserved<BasicAAWrapperPass>();
       AU.addPreserved<GlobalsAAWrapperPass>();
     }
   };
-- 
2.7.4